I've just watched the Eurogamer video and it's really looking pretty special. (btw: Listen out 30 seconds into the video for some guys in the background mocking "super marios!!! Hello super marios!!! Are you having fun?".
There are 2 things that, if possible, would be pretty cool in the final design:
button on stylus - seeing the turning/shooting troubles on metroid DS, this would be really useful.
Force feedback stylus - This would be the icing on the cake. There's this funny 'carving' techdemo on the vid, where the stylus is beeing used as an electric saw. I thought it looked pretty cool that where the stylus touches, off-cuts and chips fly everywhere and this buzzzz sound. It's quite a weird effect seeing the pen used like this, and a rumble feature would just add that bit more.
Also, I'm not sure about the PSP-style love-handles on the final design.
[edit]Oh, and is that little red arrow really necassary? Afterall, there is a 6 inch pen already pointing where you aim.